Geared Candle Holder

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What began as a simple how-to article about making gears has turned into a major project article for Make Magazine and at last is published in volume 21. The project is candleholder with three gears and parallel action arms which move the candles up and down at different rates. In many ways, it is similar to my first candleholder, but this one is made from aluminum plate and uses tea lights or small floating candles. The design and the variable gearing also make it a more playful device.

On the project page here, I have posted all the images from the construction process (many more than in the published article) as well as some additional charts and diagrams which can supplement the material in the article. Hopefully these materials can help out with some of the more tricky parts of the project. If you have any questions, want a CAD file, or would like to share photos of you project, send me an email!

Here are most of the tools and materials I used in creating this project.

Materials and tools

My sheet of 1/4" aluminum plate, purchased from Metal Supermarkets.

aluminum plate

A layout diagram showing the dimensions and calculations for making gears.

gear dimension

Using a clear protractor and scribe to mark degrees around the center of a gear. Simply divide 360 bythe number of teeth to get the degree increments: 15 teeth need marks every 24 degrees (15*24=360).

Using protractor

Setting dividers using digital calipers. This is not a precise method, but it works in a pinch and saves the time of converting thousanths of an inch into fractions.

setting dividers

Marking the outer circle of a gear. You can see the center punch marks in place for the gear teeth.

Outer circle

Marking a circle for the connecting rod hole in a gear. Only a small segment of this circle is actually needed, as the hole can be located anywhere along it.

inner circle for con rod

Drilling the gear teeth.

Drilling gear

A drilled-out gear ready for cutting.

rough drilled gear

Cutting a gear on a vertically mounted portable bandsaw. This is a useful modification if you cut a lot of plate. For this operation, a hacksaw would also be efficient.

sawing gear

I find it easiest to cut in from one side first, then the other, to begin the tooth profiles.

Each tooth must then be filed to a half-round shape to match the gaps between them. They will still work if they are a bit small, but if they are too large they will bind.

filing gear

Aluminum is soft and files very easily. This does not take as much time as it could. Nevertheless, if you have a belt sander, much of this operation can be done there.

filing gear detail

Testing the gears on a piece of scrap wood. I mark trouble-spots with a sharpie to contine filing.

testing gears

A 10-24 tap in a tap handle. If you are ordering parts for this or other projects from Mcmaster Carr or another supplier, consider ordering some good quality taps, as they work much better than the average hardware store products.

Tap in handle

Tapping a gear.

tapping gear

A layout chart for the backplate. If you use the bottom edge as a reference and place the gears roughly where they fit together without binding, you can use dividers to triangulate the rest of these dimensions.

backplate chart

Using the bottom edge of the aluminum plate as a reference edge.

 

Bottom edge as reverence

Fitting the gears along reference marks and center punching with a transfer punch.

 

locating gears on backplate

Using dividers to triangulate locations on the backplate

 

using dividers on backplate

Using an oval template to fill in the outline of the backplate

 

oval template on backplate

Outline of the backplate ready to drill and cut.

 

backplate outline

Cutting inside curves made easier by making sections.

 

cutting backplate

The backplate, drilled and roughly cut.

 

roughcut backplate

Tapping holes in the backplate.

 

tapping backplate

Filing the edge of the backplate.

 

filing backplate

Using a transfer punch to mark the first hole in the front plate. Bottom edges must be aligned.

 

transfer punch to frontplate

Use a 1/4" pin or rivet to match the front and back plates together.

 

pin through frontplate

Then clamp with bottom edges aligned to drill the remaining holes.

 

drilling front plate

The transferred holes in the front plate (below).

 

frontplate after drilling

Drilling through both a clamp-on collar and pinion with a 1/16" bit. A 1/4" pin holds the two parts aligned so that when they are joined they fit together on the 1/4" axle which also holds the knob.

 

drilling pinion

Fitting a 1/16" tension pin into the hole just drilled. This effectively joins the collar to the pinion, making a strong, yet removeable, mechanical joint. You will need a small hammer to push the tension pin all the way in.

 

tension pin in pinions

This is my layout for the knob, which was made as a five-tooth gear with 1/2" diameter teeth.

 

marking knob

The knob, cut and filed.

 

knob cut and ready

The knob with collar attached.

 

knob with collar

Here are the feet of the candleholder, cut and ready for shaping.

 

feet rods

A foot with roughly cut slots for the front and back plates.

 

rough cut feet

The two feet, cut and filed and ready for attachment

 

filed feet

A chart showing the dimensions for the connecting and parallel arms. Red dimensions indicate hole diameter, blue dimensions show distance from center to center of holes

 

arms lengths

It is often just as easy to drill two holes at once.

 

drilling arms

Testing out the connecting and parallel arms.

 

testing arms

Here is a top-view of the candleholder showing where the spacers go. The point of the spacers is to hold the arms in place and prevent them from operating in the same plane, which would cause them to crash into each other.

 

spacer chart

Cut and filed spacers.

 

spacers

Here you can see the construction of the candle brackets.

 

bracket layout

A candle bracket disc, with holes marked and drilled.

disc with holes

One part of the candle bracket, with pins cut and filed to fit into 9/64" holes.

 

bracket posts

A candle bracket ready for pins to be staked. A spare piece of aluminum is placed between the brackets to hold them securely in place.

 

bracket ready to stake

Staking the pins using a center punch.

 

staking posts

Aluminum is relatively soft, but will begin to crack if pushed too far. Here are the staked pins holding the bracket parts together securely.

 

posts staked

The top of the disc and pins are sanded.

 

posts sanded

Here a candlecup is in place and ready to be glued.

 

ready to glue

I used one minute epoxy to fix the cups in place, but hot glue would work as well.

 

gluing cup

Here are some wave spring washers, which help to put tension on the movement so the the candles, which are pushing down on the mechanism, do not fall down.

 

wave washers

Using blue (removeable) threadlocker to make sure all the screws stay tight unless you want to take the machine apart later.

 

using threadlocker

Here are several images of the candleholder in movment. The surface has just been smoothed with scotchbrite pads, but no other coating is required.

 

Candleholder in motion
   
   
   
   
   
   
   

 

 

 

 

  Manifold Ballast, edition of ten
Price: $700 +shipping/handling (or pick up in Bay Area)
Paypal, check, or money order accepted
email to arrange.

Questions? Comments? Want to see larger images? Interested in displaying or purchasing this item?
Email me at ben@twentysevengears.com

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